diff --git a/src/12/c14/c14_lv255.cpp b/src/12/c14/c14_lv255.cpp
new file mode 100644
index 0000000..46e1c60
--- /dev/null
+++ b/src/12/c14/c14_lv255.cpp
@@ -0,0 +1,51 @@
+#include <cstddef>
+#include <iostream>
+#include <ostream>
+#include <vector>
+
+using namespace std;
+
+template<class T>
+ostream&operator<<(ostream &os,vector<T> const& v){
+    os<<"{ ";
+    if(v.size()==0){
+        os<<" }";
+    }else{
+        for(size_t i=0;i<v.size()-1;i++){
+            os<<v[i]<<" ,";
+        }
+        os<<v[v.size()-1]<<" }";
+    }
+    return os;
+}
+
+vector<int> getPrimes(int const& end){
+    vector<bool> isFactor(end+1,false);
+    for(int i=2;i<end;i++){
+        if(isFactor[i]==false){
+            for(int j=i+i;j<end;j+=i){
+                isFactor[j]=true;
+            }
+        }
+    }
+    vector<int> primes;
+    for(int i=2;i<end;i++){
+        if(isFactor[i]==false){
+            // cout<<i<<' ';
+            primes.push_back(i);
+        }
+    }
+    return primes;
+}
+
+int main(){
+    // const auto primes255 = getPrimes(2500+1);
+    vector<int> nums(5,0);
+    for(auto const& i:getPrimes(1e5)){
+        nums[i%5]++;
+    }
+    for(int i=0;i<5;i++){
+        cout<<i<<" : "<<nums[i]<<'\n';
+    }
+    cout<<'\n';
+}
\ No newline at end of file
diff --git a/src/12/c14/c14_prime.cpp b/src/12/c14/c14_prime.cpp
index f77ee0b..68902b0 100644
--- a/src/12/c14/c14_prime.cpp
+++ b/src/12/c14/c14_prime.cpp
@@ -1,7 +1,6 @@
 #include <cstddef>
 #include <iostream>
 #include <ostream>
-#include <type_traits>
 #include <vector>
 
 using namespace std;